The present invention relates to improvements in moving picture cameras with interchangeable film magazine.
Moving picture cameras are already known in which the energy necessary for rotating the drive friction of the take-up roll of the magazine is not taken from the main motor of the camera, but a motor housed in the magazine is used to this end, which delivers the energy necessary for winding the exposed film at a sufficient tension. Such is the case, for example, of high capacity moving picture cameras or ones which must operate at low temperatures.
In these known cameras, the electric motor incorporated in the magazine is not servo-controlled and it rotates at a sufficiently high speed to be able to drive the exposed film when the spool of film formed on the take-up roll has a small diameter, and with a sufficient torque to be able to drive this spool by creating a sufficient tension of the film when the spool formed has its maximum diameter. Consequently much more electrical energy than is necessary is consumed and this leads to a shortening of the useful life duration of the incorporated source of electric energy which is used in the camera.